Human growth hormone binding and stimulation of insulin biosynthesis in cloned rat insulinoma cells.

Binding of 125I labelled human growth hormone to cloned insulin producing RIN-5AH cells is described. Binding was specific for somatotropic hormones since both human and rat growth hormone could compete for binding sites, whereas much higher concentrations of lactogenic hormones were needed to inhibit binding. Culture of RIN-5AH cells in the presence of hGH stimulated insulin biosynthesis by 85%.